Independently and not as an agent of the Government, the Contractor shall perform studies on new in vitro techniques or make substantial midifications of existing techniques for evaluation of cell-mediated immunity to tumor associated anitgens. Specifically, the Contractor shall: Investigate the usefullness of 86Rb release from target cells as an early and more sensitve indix of cytotoxicity, as compared to 51Chromium release; Covalently couple saluble tumor antigens to 51Chromium-labelled erythrocytes and to P815 cells and use these cells as targets of specific cell-mediated immunity, in cytotoxicity assays; Investigate use of gluteraldehyde-fixed tumor cells for stimulation of syngeneic immune lymphocytes as measured by incorporation of 3H-leucine, 3H-uridine, and 3 H-thymidine; and performed these studies in syngeneic mouse tumor systems, utlilizing outochtonous or recently derived tumors. The selection of the syngeneic tumor systems is subject to the approval of the Project Officer.